As the president and chief executive officer of the stock platform IEX, Katsuyama catapulted to fame after the March publication of “Flash Boys,” a book by Michael Lewis that casts the 36-year-old Wall Street veteran as a bulwark against vulture high-frequency traders.

Although his starring role in the book instantly changed his life, from overflow meetings with industry bigwigs to getting recognized on the street, his fight to make the industry more fair hasn’t gone so quickly — or easily.

“I’ve developed a good relationship with Billy Beane,” he told The Post, referring to the general manager of the Oakland A’s and star of an earlier Lewis book, “Moneyball.”

“[Beane] called me at the end of the first week [the book was out] and said, ‘the critics will always be loudest early on,’ ” Katsuyama said. “He faced the same thing.”

But that could start to change.

In a major speech on high-frequency trading (HFT) this week, Securities and Exchange Commission Chair Mary Jo White said she’s receptive to systems “designed to minimize speed advantages” — exactly what IEX sets out to do.

In Katsuyama’s office, which looks out over the 9/11 memorial from 7 World Trade Center in downtown Manhattan, a coffee mug with an illustration from the cover of “Flash Boys” — a bull with lightning bolts as horns — sits on his desk.

IEX, which started in October, is an anomaly of a trading platform because it slows every trade to the same speed so that everyone has the same shot at a stock.

HFTers pay exchanges like Nasdaq huge sums of money to put their computer closer to the exchanges’ mainframes, cutting down trade times by microseconds and giving them an edge over others. That practice is called “co-location.”

With that head start, HFTers can buy up a stock on Nasdaq for one price, and then sell it on another exchange for a penny higher. There are 60 million microseconds in one minute.

“ ‘I’m just going to take a little bit from everyone and make myself rich,’ ” he said, characterizing the attitude of the HFT sector.

“That’s not the foundation of this country,” Katsuyama said. “That’s not the foundation of capitalism. That’s cheating.”

IEX’s plan to reshape the trading landscape is going slowly but Katsuyama said his battle is in the “second mile of the marathon.”

Katsuyama has plans to double IEX’s average volume to about 1 percent of trading and hire salespeople to handle the rising number of meetings. He’s shooting for a valuation of around $300 million.

He’s also put IEX on the fast track to become a registered exchange, which would put it among trading venues like the New York Stock Exchange and BATS.

That process could take about a year, he said.

“At this point in time, people might be able to justify why they can ignore us, because we’re a startup and we’re new,” he said. “At some point, you reach a point of critical mass where that argument self-destructs.”

“Flash Boys” paints Katsuyama, who was born in Canada, as an unassuming but determined hero who is trying to correct entrenched biases in the stock market.

In one widely circulated quote from the book, he refers to himself in the third person as the only person who is fighting for what’s right.

It sounds like it’s straight from a Hollywood blockbuster.

Lewis, in fact, took some creative license with the quote, Katsuyama said.

“Did he capture the essence of what I said to my wife? Yes,” Katsuyama said.